1. Field of the Invention
The present invention relates to the High Definition Multimedia Interface (HDMI), and specifically to the conversion between different formats of HDMI video signals.
2. Prior Art
There are many component video formats in use. The most commonly used component video formats are RGB, YPbPr and YCbCr. The RGB format is the basic format in which the signal is generated in the video camera. In other formats the Y component of this signal is the black and white information contained within the original RGB signal. The Pb and Pr signal are color difference signals, which are mathematically derived from the original RGB signal. It is important to realize that what is commonly called “component video” (YPbPr or YCbCr) output and RGB video output are not the same and are not directly compatible with each other, however, they can be converted either way.
Advanced Television Systems Committee (ATSC) is a committee which specifies the digital TV broadcasting system in use in the USA. This standard supports both standard definition (SD) and (HD) broadcasts. There are 18 approved formats for digital TV broadcasts covering both SD (640×480 and 704×480 at 24p, 30p, 60p, 60i) and HD (1280×720 at 24p, 20p, and 60p; 1920×1080 at 24p, 30p and 60i).
HDMI has the capacity to support existing high-definition video frame and display formats (720p, 1080i, and 1080p/60). It also has the flexibility to support enhanced definition video frame and display formats such as 480p, as well as standard definition formats such as NTSC or PAL.
Currently there are a number of Video formats, each with its own ordered data streams having a specific sequence. There has been no common mapping facility which can be easily implemented as part of an integrated circuit to map these sequences into other usable video data sequences.